Thread-controlling device



Sept. 7, 1943. R. BECKER I THREAD-coNTRoLLINc- DEVICE Filed Feb. 281,194? 2 Sheets-Sheet l @www Patented Sept. 7, 1943 omiso 'STATES Param]lorries;

` rnnnnns'oonrnonmseinnvioe Y iaueipifyneckeanortn Plainfield, N. 1.,-assig11or Y tozThe SingenManufactur-ing Company, Eliza'- g l "beth, Nl J., a corporation oif`New Jersey .Applicatienfrebruary 2s, 1942, "serial 1110.432335 7 claims. (o1. 1112-201) This 'invention relates to sewing machines and more particularly to the Ystitch-forming instrumentalities of the single-thread chain-stitch rotary looper type sewing machine. v

It certain classes of Work,v such as necktie stitching, exceptionally loose stitches arerequired to give the resultant seam the proper'amount of elasticity. In order to producev such loose stitches an exceptionally large loop` ofthread must be drawn out of the' rising needle and as this loop, when shed by the looper, is not set tightly up to the Work by the take-up mechanism, it requently happens that this loosely drawn up needle-thread loop is reseized by the looper Vbeforethe loose stitching is drawn upthrough the needle-aperture Vin the throat-plate by'the action of the feeding mechanism. It is, therefore, an object of the present invention to overcome the above cited stitching dimculties by provision of a thread-guard or delector for the looselysetup needle-thread loops, Which'will prevent reseizure of'such loops by the looper before they are fed out of `range of the looper. l

With the aboveand'otherobiectsinfview, as will hereinafter appear, the invention comprises the devices, Vcombinations and arrangements of parts hereinafter set forth and-illustrated inthe accompanying drawings of a preferred embodiment of theinventio-n, fromv which the `several features of the invention Vand the advantages attained thereby will be' readily understood by those skilled in the art. l

In the accompanying drawings, Fig. 1 is a `front elevation of a sewing machine embodying the present invention. l

lFig. 2 isa left end View of the machine shown in Fig. 1. f

"Fig 3 is a'bottom plan View of the' elements upon the underA side of `the Work-support adjacent the sewingpoint. f

Fig. "lis-a` sectional elevatiomon an enlarged scale-of 'the Work-support and the stitching instrumentalities shown in Fig. 2. f .u

4Figu isa bottom plan-view ofthe throat-plate with the present linvention applied:'tllereto.`

Fig. 6 is a sideview of the thread-'guardshoivn innig. 5. Y j

7 is a bottoniplan View of a'section of fabric containing a' line of loosely set 'up singlethread chaingstitches.

Fig. `8 Yis avertical "section""takenfsubstantlally along line8-8 of Fig. 7. y i' Referring 'more "Specifically to fthej drawings, the invention is disclosedas .embodied in'fasewing lachrle'havng" a frame""'co"mprising Aa"b'a's`e ri,

iss

standard `I I, and `an overhanging arm l2 Awhich terminates in a hollow head it. A main. or needle-bar-actuating Vshaft ill is journaled 'length- Wise ofthe arm I2 and mounted Yat its rearj'end is a combined belt- [and hand-Wheel i5. "The forward end ofthe "shaft i4 actuates, by means.

.not herein shown, a reciprocatory needle-bar 'S which is suitably journalecl in the head 'i 3 and carries an eye-pointed needle il at its lower end. Also mounted in thehead t3 is a spring-pressed presser-bar I8 to the -lower end of which is secured,A asby a clamp-screw i9, a presser-foot 20;

Cooperating vwith the presser-foot 2E! to effect step-by-step movements ci the Work between-successive reciprocations of the needle Il, isa feeddog r2l which operates through slots 22 inthe throat-plate V2?. This feed-'dog 2| is adapted `to be` given backward-and-forward' and rising-Landfalling movements such as'are commonin conventionalv four-motion `feeding mechanisms.

These movements are effected by suitable mechanism located Within the basalt-of themachine. A more detailed disclosure of the present -feeding mechanism-'may loe-had by reference tomy U. S.

. Patent No. 2,222,017, dated-NOW 19, 1940.

`lvountedinfthe base 'lil -of the machine is L'a rotar'ywshaft 2li carrying upon 'itSouterfend a conventional "rotary Wing-type chain-stitch looptakerZS which cooperates with the needle "I1 in the formation of single-threadl chain-stitches.

Suitable mechanism Within themachine framel effects rotation of the loop-taker 1in-timed relation with the reciprocations ofthe needle? I-T. For a 'more complete disclosure of the vpresent loop-taker and needle-'actuating mechanisms referencemay be @had to my IU. S. vPatent No. 2,222,016, dated.l*l `Jv.. 19, 1940.

The. machine *is also 'itted with the thread- Controlling and take-up mechanisms of my patent application Serial No. 423,1914piiled Dec. 22, 19411, and comprising -essentially the needle-"bar thread take-up element 28,.` the pull-oir arm `2"! cooperating with thethread-guardl, `the double diskftension '23, andthe thread-nipperunit 29. The'needle-thread is delivered from a supply source, not-herein shown, directly tothe usual double disk 4tension unit 128' from-Which it is threaded throughthe eyelets` of .the threadguide-3|, `and thenit is ledloackvvardlyA through a stationary eyeletf to `the thread-nipperunt 29. Fr-0in the `nipp'er-unit the threadislediforwardly through a pair of stationary eyelets-33 'directly to 'astatienary 4tlneacl-gulifde gener-ally designatedby the nume' its. @thaliana-thread is ldf-lremltheguideftotlie ye'oflthe take-up chain-stitch sewing machines .an relongated needie-aperture is required so that proper room will be provided'for both the rising cast-off needleloop and the descending thread-carrying needle.

Mounted upon the bottom surface of the throat-plate 23 by `means of a fastening screw 39 is the shank 40 of the thread-guard having a reduced portion 4l and an active edge 4?.. The fastening screw 39 passes through an enlarged aperture 43 in the thread-guard thereby permitting the thread-guard to be adjusted lengthwise and sidewise of itself. As may be best seen in Figs. 4 and 5, the thread-guard is disposed inparallel relation with the throat-plate and the active edge 42 is spaced from the throat-plate andunderlies and extends across the elongated needle-aperture 38, in a direction transverse to the direction of feed.y Having the active portion 42 of the thread-guard spaced from the throatplate 23r prevents the cast-off needle-loop 50 from being caught between. the throat-plate and the thread-guard.`

Figsf? and 8 illustrate a body material 44 having a line of loosely set-up single-thread chainstitches placed therein. It is to be noticed thatv in orderto provide the proper amount of elaspending from beneath the under surface of the material. l In Fig. 4 of thedrawings, the needle Il has just begun to riseand the beak 48 ofthe looper is about to enter the needle-thread loop 41 formed by the rising needle and it is also about to enter the loop 48 of thread previously expanded by the looper and detained at this time in the throat 46 thereof. Just prior to this time the loop 5I!` was cast off from the looper and it was drawn up through the needle-aperture by the combined actions of the take-up and feeding mechanisms. However, the loop 50 being abnormally large, is not drawn up sufliciently close to the work to eliminate danger that the loop 5G will be caught a second time Aby the looper beak. Therefore, the present thread-guard has been provided so that its active portion 42 will engage the loop 5l] as the work is being fed prior to the descent of the needle and wipe such loop upwardly and in a direction opposite to the direction ofv feed, thus removing the loop from the path of the looper. As shown in Fig. 4, the active portion 42 of the thread-guard is sustaining the loop 50 in its upwardly deected position and therefore the looper beak 48 cannot engage the same. When theneedle Il rises completely out of the fabric 44 the feeding mechanism will shift the work past the needle-aperture to thus completely vdrawthe loop 50 up through the needleaperture.

Having thus setforth the nature of the Iinvention what I claim herein is: l

:1.,In a sewing machine, vin combination, a

thread-carrying needle, means for reciprocating said needle, a rotary chain-stitch looper cooperating with said needle in the formation of stitches, needle-thread take-up means, a throatplate, means to feed the work over the throatplate, and a thread-guard disposed below said throat-plate, said thread-guard'being adapted tov engagevthe cast-01T needle-loopand to deflect saidy loop upwardly and in a direction opposite to the direction of feed.

2. In a sewing machine, in combination, worklfeeding means, a thread-carrying needle, means Y for reciprocating said needle, a looper cooperat- ISU ing with said needle in the formation of stitches,

said looper having yits loop-seizing movement in the direction ,of the feed ofthe work,v needlethread take-up means, a throat-plate having a needle-aperture, therein, and a thread-guard having its active portion underlying and extending across said needle-aperture at a point rearwardly of the needle-path, said thread-guard bev ing adapted to engage the cast-off needle-loop and to deiiect said loop upwardly and in a direction opposite to the direction of feed. 3. In a sewing machine, incombination,r workfeeding means, a reciprocatory thread-carrying. needle, a chain-stitch looper having its loopseizing movement in the direction ofV the feed of the work, and needle-thread take-up means all cooperating in the formation of loosely setup sitches, a throat-plate provided with a needle-l aperture therein, and a thread-guard having its active portion underlying. and extending across said needle-aperture in the rear of the needlepath, said work-feeding means being adapted-'to draw each cast-off needle-loop over the active portion of said thread-guard soas to deflecteach loop upwardly and in a direction opposite to Yth direction of feed.

4. In a sewing machine, in combination, `a' reciprocatory thread-carrying' needle, a rotary chain-stitch looper and needle-thread take-up means, all cooperating in the formation of loosely set up stitches, a throat-plate having an elongated needle-aperture therein, work-feeding means, and athread-guard having its active `portion underlying and extending across said elongated needle-aperture in the rear of the needlepath, 'said work-feeding means being adapted to draw each cast-off needle-loop over the active portion of said thread-guard so as to deflect each loop upwardly and in a direction opposite to the direction of feed. l l

5. In a sewingmachine, in combination,.,a`

work a component ofrmovement in the direction of loop-seizing movement of the looper, said feeding means being also adapted to draw each-of said loosely set up needle-thread loops over the active portion of said thread-guard so as to deilect each loop upwardly and in a direction opposite to the direction of feed. Y

6.4 Ina sewing machine, the combination with a thread-carrying needle, means to actuate said needle, a .rotaryuchain-stitch looper cooperating with said needle in the formation of stitches, Workfeeding means operative to feed the Work` in one direction, and a throat-plate having a needleaperture therein, of a thread-guard secured t0 and in parallel relation with the bottom surface of said throat-plate, said thread-guard comprising a substantially `ilat metal strip having one edge thereof underlying and extending across said needle aperture at a point rearwardly of the needle-path and in a direction transverse to the direction of feed, said thread-guard cooperating with said Work-feeding means so as to deect each cast-01T needle-loop upwardly and in a direction opposite to the direction of feed.

7. A sewing machine having, in combination, a reciprocatory thread-carrying needle, a platemember provided with a needle-aperture through which said needle reciprocates, a loop-taker positioned at one side of said plate-member and complemental to said needle in seizing a threadloop Vpresented by said needle and enchaining said thread-loop with a preceding thread-loop expanded by saidloop-taker prior t0 casting off said expanded thread-loop, a feeding mechanism for advancing Work past said needle, and a member extending across the line of feed rearwardly of the path of needle-reciprocation and providing an abutment against Which the cast-olf threadloop is moved by the advance of the Work to deflect said cast-off loop out of range of the loop-taker as the latter advances to seize a subsequent needle-thread-loop.

` RUDOLPH BECKER. 

